scholarly journals X‐Ray Observations of the Coma Cluster in a Broad Energy Band with theINTEGRAL,RXTE, andROSATObservatories

2008 ◽  
Vol 687 (2) ◽  
pp. 968-975 ◽  
Author(s):  
A. A. Lutovinov ◽  
A. Vikhlinin ◽  
E. M. Churazov ◽  
M. G. Revnivtsev ◽  
R. A. Sunyaev
Keyword(s):  
Energy Band ◽  
Coma Cluster ◽  
X Ray ◽  
Broad Energy

scholarly journals The Constellation X-ray Mission

2000 ◽  
Vol 195 ◽  
pp. 61-68
Author(s):  
N. E. White ◽  
H. Tananbaum
Keyword(s):  
High Resolution ◽  
Spectral Resolution ◽  
Energy Band ◽  
High Spectral Resolution ◽  
X Ray ◽  
Increased Sensitivity ◽  
Similar Factor ◽  
Area X ◽  
The Universe ◽  
Broad Energy

The Constellation-X mission is a large collecting-area X-ray facility emphasizing observations at high spectral resolution (E/ΔE ~ 300–3000) while covering a broad energy band (0.25–40 keV). By increasing the telescope aperture and utilizing efficient spectrometers, the mission will achieve a factor of 100 increased sensitivity over current high-resolution X-ray spectroscopy missions. The use of focusing optics across the 10–40 keV band will provide a similar factor of 100 increased sensitivity in this band. When observations commence in ~ 2008, Constellation-X will address many pressing questions concerning the extremes of gravity and the evolution of the Universe.

Energy Band Gap Studies of CdS Nanomaterials

2008 ◽  
Vol 3 ◽  
pp. 97-102 ◽  
Author(s):  
Dinu Patidar ◽  
K.S. Rathore ◽  
N.S. Saxena ◽  
Kananbala Sharma ◽  
T.P. Sharma
Keyword(s):  
Optical Absorption ◽  
Band Gap ◽  
Energy Band ◽  
Chemical Method ◽  
Optical Absorption Spectroscopy ◽  
Cds Nanoparticles ◽  
X Ray Diffraction ◽  
Energy Band Gap ◽  
X Ray ◽  
Simple Chemical

The CdS nanoparticles of different sizes are synthesized by a simple chemical method. Here, CdS nanoparticles are grown through the reaction of solution of different concentration of CdCl2 with H2S. X-ray diffraction pattern confirms nano nature of CdS and has been used to determine the size of particle. Optical absorption spectroscopy is used to measure the energy band gap of these nanomaterials by using Tauc relation. Energy band gap ranging between 3.12 eV to 2.47 eV have been obtained for the samples containing the nanoparticles in the range of 2.3 to 6.0 nm size. A correlation between the band gap and size of the nanoparticles is also established.

scholarly journals Limits on mass outflow from optical tidal disruption events

2021 ◽  
Vol 502 (3) ◽  
pp. 3385-3393
Author(s):  
Tatsuya Matsumoto ◽  
Tsvi Piran
Keyword(s):  
Energy Band ◽  
New Method ◽  
Hydrodynamic Modelling ◽  
X Rays ◽  
Will Emit ◽  
Tidal Disruption ◽  
X Ray ◽  
Mass Outflow ◽  
Current Sample ◽  
Stellar Masses

ABSTRACT The discovery of optical/UV (ultraviolet) tidal disruption events (TDEs) was surprising. The expectation was that, upon returning to the pericentre, the stellar-debris stream will form a compact disc that will emit soft X-rays. Indeed, the first TDEs were discovered in this energy band. A common explanation for the optical/UV events is that surrounding optically thick matter reprocesses the disc’s X-ray emission and emits it from a large photosphere. If accretion follows the super-Eddington mass infall rate, it would inevitably result in an energetic outflow, providing naturally the reprocessing matter. We describe here a new method to estimate, using the observed luminosity and temperature, the mass and energy of outflows from optical transients. When applying this method to a sample of supernovae, our estimates are consistent with a more detailed hydrodynamic modelling. For the current sample of a few dozen optical TDEs, the observed luminosity and temperature imply outflows that are significantly more massive than typical stellar masses, posing a problem to this common reprocessing picture.

scholarly journals Effect of Dopant Concentration on the Structural, Optical and Sensing Properties of (SnO2)1-x(TiO2:CuO)x Sprayed Films

2019 ◽  
Vol 16 (2) ◽  
pp. 0361
Author(s):  
Mahmood Et al.
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Energy Band ◽  
Spray Pyrolysis Technique ◽  
Single Crystal Silicon ◽  
Dielectric Constants ◽  
Energy Band Gap ◽  
Crystal Silicon ◽  
X Ray ◽  
Regular Manner

      Spray pyrolysis technique was subjected to synthesized (SnO2)1-x (TiO2: CuO) x Thin films on different substrates like glass and single crystal silicon using. The structure of the deposited films was studied using x-ray diffraction. A more pronounced diffraction peaks of SnO2 while no peaks of (CuO , TiO2 ) phase appear in the X-ray profiles by increasing of the content of (TiO2 , CuO) in the sprayed films. Mixing concentration (TiO2 , CuO) influences on the size of the crystallites of the SnO2 films ,the size of crystallites of the spray paralyzed oxide films change in regular manner by increasing of (TiO2 , CuO) amount. The effect of mixing concentration on the optical properties of the films was also investigated. The reflectance and transmittance spectra  in the wavelength range (300-1100) nm were employed to determine the optical properties such as energy band gap (Eg) and refractive index (n),  extinction coefficient  (k) , real and imaginary parts of dielectric constants (ε1, ε2) for (SnO2)1-x(TiO2:CuO)x films. The energy band gap omit of which showed reduction from (3.65 to 2.2) eV by reducing of SnO2 amount from (100 to 70) % .The reduction of energy band gap was ascribed to the new tail states introduced in the band gap of tin oxide. The sensitivity of the prepared sensor film was determined resistance difference of the films when exposed to oxidizing gas. The data declared that the mixed SnO2 films have better sensitivity in comparison with unmixed films.

scholarly journals X-ray observations of a subhalo associated with the NGC 4839 group infalling toward the Coma cluster

2016 ◽  
Vol 68 (5) ◽  
pp. 85 ◽  
Author(s):  
Toru Sasaki ◽  
Kyoko Matsushita ◽  
Kosuke Sato ◽  
Nobuhiro Okabe
Keyword(s):  
Coma Cluster ◽  
X Ray

80 MHz Survey of Extra-Galactic X-ray Sources

1979 ◽  
Vol 3 (5) ◽  
pp. 332-341 ◽  
Author(s):  
O. B. Slee ◽  
P. J. Quinn
Keyword(s):  
Angular Size ◽  
Virgo Cluster ◽  
Relativistic Electrons ◽  
Clusters Of Galaxies ◽  
Coma Cluster ◽  
Microwave Background ◽  
Significant Information ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Bremsstrahlung Emission

The completion of the Uhuru (Forman et al. 1978) and Ariel V (Cooke et al. 1978) surveys of the sky for X-ray emission has resulted in many proposed identifications with individual galaxies and clusters of galaxies. The X-ray positions are not usually accurate enough to enable a positive identification to be made of the X-ray sources with optical or radio objects, and hence the identification is often based on statistical arguments — viz., the unexpected occurrence of unusual galaxies, radio sources or clusters of galaxies within or near the X-ray error boxes. There is usually no significant information available on the angular size of the X-ray emitter but in two or three cases (e.g. Perseus cluster, Coma cluster and Virgo cluster) the angular resolution is good enough to identify a broad component with dimensions approaching those of the whole cluster. This extended X-ray emission has been ascribed to either inverse Compton scattering of the 3° microwave background by relativistic electrons in the intra-cluster medium or to thermal-bremsstrahlung emission by an optically thin plasma at - 10s K.

scholarly journals Diagnostic Signatures of Radio and Hard X‐Ray Emission on Particle Acceleration Processes in the Coma Cluster

2003 ◽  
Vol 594 (2) ◽  
pp. 732-740 ◽  
Author(s):  
Ping‐Hung Kuo ◽  
Chorng‐Yuan Hwang ◽  
Wing‐Huen Ip
Keyword(s):  
Particle Acceleration ◽  
Coma Cluster ◽  
X Ray
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